Retargeting
Media buyingShowing ads to users who already interacted with your funnel — visited the landing page, added to cart, or watched a video — but didn't convert. Because these people know your offer, retargeting audiences usually convert cheaper and higher than cold traffic, making it a staple for squeezing more ROI out of the same spend. You build the audiences from pixel data or uploaded customer lists.
Example
Serving a discount banner to everyone who reached checkout but never paid.